Sure. You can add a Calculation field with the following function:
DATE(Date Field; "MM")
Tell the formula to return a Text value and it will display 01 – 12 for the month numbers extracted from the Date.
If you truly want a Number value rather than a Text value that looks like a number, then use the STR2NUM() function to turn the result into an actual numeric value that you can use in other math type functions.
This reply was modified 2 weeks, 1 day ago by Brendan.